AA S410 classic custom hammer

[Stefan]

I've been tinkering with my 12 ft/lbs AirArms S410 Classic in .22. I'm not from UK.
I have managed to push the power up to 26 joules wit simple mods. Now, I got a regulator for it, and I wanted more power.
I've made myself a new hammer. The stock one is 46 gram heavy, and mine custom made is 56 grams
The spring is stock, with stock preload (overall dimensions are the same, except one that is thicker).
My question is what are possible benefits of heavier hammer? I haven't chronied it yet. I have to send it to hardening I suppose(please advise)?
Also, I cant find a solution for small bushing that stock hammer has - could brass sleeves replace them?

custom made on my mini lathe



stock and custom side by side (left to right)

[kelly1]

Looks like you could order part S520-1,striker bush.2 ea. from Air Arms or any parts stocking retailer..kelly
pm. if you need the manual

[Stefan]

thanks for the offer, I got it
yes thats the part, but here we dont have AA representative, nor the some retailer has these spares in stock. Thats why I was considering making a brass ones.

[Motorhead]

Funny ... having just finished tuning an M-rod with regulator, found after some testing power went up along with efficiency going to a hammer @ 1/3 the weight of factory one.
All that increased mass opens valve further, but also valve opens and closes slower.
With valve needing less impact due to lower internal pressure, more weight is radically increasing dwell.
Get valves internals to flow better, pressure pulse driving pellet peaks quicker and you can get away with less dwell.

May want to play with different weights keeping spring and preload the same.  Watch what velocity does as weights go above and below the sweet spot.
You may find as I did that if you can get correct weight for spring rate fitted valves operation will be excellent giving you the best of both ... Power and Efficiency

JMO...
Scott

[Stefan]

thanks for the reply and ideas.
I dont have the sweet spot, since I installed regulator in it. Tonight I assembled it with stock hammer and I'll chrony it on Saturday (if it gets a bit warmer lol, its -15 C here).
I'll post the results.

[kelly1]

thanks for the reply and ideas.
I dont have the sweet spot, since I installed regulator in it. Tonight I assembled it with stock hammer and I'll chrony it on Saturday (if it gets a bit warmer lol, its -15 C here).
I'll post the results.

Hi,which reg. did you go with?
When you get a chance show us a shot string...kelly

[Stefan]

its an altaros.cz regulator. today, with stock hammer and port opened fully, from 190 bar to just above 150 bar I got 30 consistent shots, from 746 fps to 757 fps. it was too cold to shoot the rest
tomorrow, I will install heavier hammer (that got bronze bushings now) and let you know both strings result.

[rsterne]

In general terms, a heavy hammer does what a heavy hammer spring, increasing the preload, or a longer hammer travel does.... They all increase the hammer strike (energy, momentum, or both).... That allows the hammer to open the valve against a higher pressure.... IF (and it's a big IF) you gun is being limited in FPE by the hammer strike, then any (or all) of the above solutions will generally increase the power by allowing you to use more pressure....

Here's the catch.... At any given pressure, for any given gun, the fps and FPE will level out (or plateau) at a given level of hammer strike.... Adding more hammer strike won't increase the velocity, it will just use more air, past that point.... So you are asking what only you can answer.... Is the gun already limited by other factors, or will more hammer strike add performance?.... If it can benefit from additional hammer strike, then adding weight will help.... My guess is that if your regulator is set for less pressure than the gun is capable of utilizing, all you will do is waste air....

Bob

[kelly1]

its an altaros.cz regulator. today, with stock hammer and port opened fully, from 190 bar to just above 150 bar I got 30 consistent shots, from 746 fps to 757 fps. it was too cold to shoot the rest
tomorrow, I will install heavier hammer (that got bronze bushings now) and let you know both strings result.

Thanks for the info, I have a Robert Lane reg.on the way for my S400 xtra fac in 22 cal..
I'm not sure if I will permanently convert the gun to reg or play with the hammer and spring and firing pot..thx..kelly

[Stefan]

rsterne was quite right. I was kinda hoping he'll answer before I try it out, but his answer came late lol.
nothing changed in fps with heavier hammer, except I used more air, for nothing
so, I returned everything back the way it was.
I will also ask Ondrej about pot number of turn ins, maybe releasing that a few turns might give more power (before adding a regulator, I had a high fps at 810-815 fps).

[kelly1]

rsterne was quite right. I was kinda hoping he'll answer before I try it out, but his answer came late lol.
nothing changed in fps with heavier hammer, except I used more air, for nothing
so, I returned everything back the way it was.
I will also ask Ondrej about pot number of turn ins, maybe releasing that a few turns might give more power (before adding a regulator, I had a high fps at 810-815 fps).

My understanding on the pot adjustment is, you can go 1mm.longer or out from stock,is your stock setting 56 or 57 mm ,do you know?

[rsterne]

Sorry it didn't work out for you, but I'm not surprised.... In your situation, there are really only two ways to increase the velocity and FPE.... You either have to add volume between the regulator output and the valve seat (which raises the average pressure during the shot).... or increase the setpoint of the regulator (which does the same thing).... At the pressure you are running, and with the port sizes you have, adding more hammer strike just wastes air.... In fact, reducing how hard the hammer hits (lighter hammer, less travel, or less spring preload) may well keep the same velocity and vastly increase the shot count.... depending on how far onto the "velocity plateau" you are running the gun with the lighter hammer.... I try and tune my regulated guns for JUST where the velocity starts to drop off below the plateau.... The efficiency takes a major jump upwards (ie a lot more shots) right at that point....

Bob